Multiple Description Coding Scheme Research Articles

Multiple Description Coding for Enhancing Outage and Video Performance Over Relay-Assisted Cognitive Radio Networks

Multimedia content delivery, such as video transmission over wireless networks, imposes significant challenges include spectrum capacity and packet losses. The cognitive radio (CR) technology is developed to solve the spectrum issue, while multiple description coding (MDC) is one of the promising source coding techniques to alleviate packet loss problems and exploit the benefit of path diversity. The source information was split into several descriptions in MDC, then transmitted over a network with multiple paths. The quality of the received data increases with the number of descriptions received at the receiver. In this paper, the proposed system comprises of relay-assisted cognitive radio network using the MDC technique for video transmission. In the simulations, the outage performance of the MDC scheme over two networks, which were relay-assisted network and non-relay network, were compared. Then, the outage probability was used to estimate the video quality, peak signal to noise ratio (PSNR) of the received video. The results obtained show the benefits of the relay assisted networks by 9% improvement on average outage performance over the non-relay network. Furthermore, the video performance improved by an average of 9% in PSNR compared to the non-relay system.

Recursive Filtering With Measurement Fading: A Multiple Description Coding Scheme

In this article, the recursive filtering problem is studied for a class of discrete-time nonlinear stochastic systems subject to fading measurements. In order to facilitate the data transmission in a resource-constrained communication network, the multiple description coding scheme is adopted to encode the fading measurements into two descriptions with the identical importance. Two independent Bernoulli distributed random variables are introduced to govern the occurrences of the packet dropouts in two channels from the encoders to the decoders. The channel fading phenomenon is characterized by the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$M$</tex-math></inline-formula> th-order Rice fading model whose coefficients are mutually independent random variables obeying certain probability distributions. The purpose of the problem addressed is to design a recursive filter, such that in the simultaneous presence of the stochastic noises, the channel fading and the data coding–decoding mechanism, an upper bound of the filtering error variance is obtained and then minimized at each time step. In virtue of the Riccati difference equation technique and the stochastic analysis approach, the explicit form of the desired filter parameters is derived by solving a sequence of coupled algebraic Riccati-like difference equations. Finally, a simulation experiment is provided to show the applicability of the developed filtering scheme.

A New Polyphase Down-Sampling Based Multiple Description Image Coding.

Multiple description coding (MDC) is an efficient source coding technique for error-prone transmission over multiple channels. In this paper, we focus on the design of a new polyphase down-sampling based MDC (NPDS-MDC) for image signals. The encoding of our proposed NPDS-MDC consists of three steps. First, we perform down-sampling on each N×N image block according to the quincunx down-sampling pattern. Second, we propose a new transform and apply it to the down-sampled pixels to produce the side descriptions. Third, we develop an error compensation algorithm to reduce the compression distortion occurring on the down-sampled pixels. In our scheme, the side decoding is performed posterior to image interpolation with reference to the down-sampled compressed pixels. Moreover, the central decoding is achieved by interlacing the side descriptions. We also propose a compression-constrained central deblocking algorithm to further improve the efficiency of the central decoding. The experimental results indicate that our proposed MDC scheme offers clearly superior performance, especially at high bit rates, as compared to the state-of-the-art methods for various types of images.

Joint Intra and Multiple Description Coding for Packet Loss Resilient Video Transmission

Multiple description coding (MDC) is a technique for video transmission over error prone networks where the descriptions are routed over multiple paths. Intra coding such as MDC provides error resiliency but coding in this mode must be decided with care since it degrades the compression ratio. In this paper, we present our investigation results for a new intra coding approach in MDC. We have found that, in MDC streams, the best policy is to encode selective frames as I-frame instead of coding some macroblocks of frames in intra mode. In order to find the most suitable I-frame positions within a given video stream, we developed a cost function based on which intra/inter frame type is decided. The MDC scheme with the proposed intra coding criterion, with and without redundancy optimization, is implemented in the H.264/AVC reference software, JM16.0. Based on the experimental performance evaluation, we show that our method achieves higher average PSNR compared to the other optimized MDCs found in the literature.

Error resilient video transmission in ad hoc networks using layered and multiple description coding

The mesh structure of ad hoc networks, provides the possibility of establishing two disjoint paths from a sender to a receiver. Transmission of video over such networks due to their unpredictability and difficulty in securing reliable channels is challenging. Layered Coding (LC) and Multiple Description Coding (MDC) are two different techniques which can benefit from path diversity for robust video communication and also to adapt with preferences of users\network. This paper presents an approach to provide error resilient video transmission over a variety of network conditions and applications needs using combined LC and MDC schemes. In the proposed method two descriptions of each layer are generated in the FMO format of the H.264/AVC standard. Unlike the conventional approaches, in our work macroblocks of each layer are divided into two paths. Hence, in the bursty error conditions the error will be smoothly spread in all layers. For better protection and more network compatibility, the base layer is data partitioned and its important part (DP_A) is repeated in both paths. Simulation results show transmission of duplicated DP_A and the non-corresponding descriptions of two layers together on disjoint paths, can improve the error concealment of the decoder and consequently enhance video quality by up to 2 dB.

Rate/distortion optimization in multiple description video coding

Multiple Description Coding (MDC) is a technique where multiple streams from a video source are generated, each individually decodable and mutually refinable. MDC is a promising solution to overcome packet loss in video transmission over noisy channels, particularly for real-time applications in which retransmission of lost information is not practical. The error resiliency feature of MDC is achieved at the cost of redundancy, and the required amount of redundancy for each frame depends on the packet loss ratio and also the importance of the frame in the sequence. Due to the error propagation in video transmission over lossy channels, reference frames of a Group of Pictures (GOP) are more important for video reconstruction and, hence, need more redundancy to increase the chance of being received correctly. Therefore a channel adaptive optimization for frame-wise redundancy allocation is needed. In this paper, based on the difference of the side and central decoder outputs, the receiver side distortion is formulated and then used for optimization of a MDC scheme. The performance of the optimizer is verified by experimental results measured from JM 16.0, H.264/AVC reference software.

Comparison and optimization of packet loss recovery methods based on AMR-WB for VoIP

AMR-WB codec, which has been standardized for wideband speech conversational applications, has a broad range of potential applications in the migration of wireless and wireline networks towards a single converged IP network. Forward error control (FEC) and multiple description coding (MDC) are two promising techniques to make the transmission robust against packet loss in Voice over IP (VoIP). However, how to achieve the optimal reconstructed speech quality with these methods for AMR-WB under different packet loss rate conditions is still an open problem. In this paper, we compare the performance of various FEC and MDC schemes for the AMR-WB codec both analytically and experimentally. Based on the comparison results, some advantageous configurations of FEC and MDC for the AMR-WB codec are obtained, and hence an optimization system is proposed by selecting the optimal packet loss recovery scheme in accordance with the variable network conditions. Subjective AB test results show that the optimization can lead to obvious improvements of the perceived speech quality in the IP environment.

Robust Image Coding Based Upon Compressive Sensing

Multiple description coding (MDC) is one of the widely used mechanisms to combat packet-loss in non-feedback systems. However, the number of descriptions in the existing MDC schemes is very small (typically 2). With the number of descriptions increasing, the coding complexity increases drastically and many decoders would be required. In this paper, the compressive sensing (CS) principles are studied and an alternative coding paradigm with a number of descriptions is proposed based upon CS for high packet loss transmission. Two-dimentional discrete wavelet transform (DWT) is applied for sparse representation. Unlike the typical wavelet coders (e.g., JPEG 2000), DWT coefficients here are not directly encoded, but re-sampled towards equal importance of information instead. At the decoder side, by fully exploiting the intra-scale and inter-scale correlation of multiscale DWT, two different CS recovery algorithms are developed for the low-frequency subband and high-frequency subbands, respectively. The recovery quality only depends on the number of received CS measurements (not on which of the measurements that are received). Experimental results show that the proposed CS-based codec is much more robust against lossy channels, while achieving higher rate-distortion (R-D) performance compared with conventional wavelet-based MDC methods and relevant existing CS-based coding schemes.

Prediction-Compensated Polyphase Multiple Description Image Coding With Adaptive Redundancy Control

In this paper, a novel multiple description coding (MDC) system is proposed, consisting of two thrust contributions: 1) a new polyphase MDC scheme, called the prediction-compensated polyphase MDC (PCP-MDC); and 2) an adaptive redundancy control (ARC) scheme for yielding optimal tradeoff between coding efficiency and error resilience. The PCP-MDC partitions each quincunx-downsampled description into two subdescriptions, called the primary subdescription (PS) and dual subdescription (DS). The PS is encoded by the H.264/AVC intra coding, while the DS is subject to prediction coding based on the reconstructed PS. For prediction, the mode-guided directional prediction algorithm is developed to conduct a fast and accurate prediction for the DS. For the second thrust contribution, two fundamental issues regarding the inserted redundancy are addressed in the proposed ARC scheme: quality and quantity. For the quality issue, the residuals of cross prediction are inserted into each description. For the quantity issue, the amount of redundancy bits allocated to each description is determined according to the network condition; for that, the probability of channel failure is incorporated into mathematical formulation on the derivation of optimal redundancy allocation condition. To implement the derived optimal condition, a fast estimation algorithm of the rate-distortion function is then developed, followed by exploiting successive approaching algorithm to identify the optimal partition of the target bitrate between the primary part of the description and its complementary part (i.e., the redundancy part). We also develop a post-processing filter, called the switching Gaussian filter, to remove the granular artifacts that tend to occur in any polyphase MDC approach when two descriptions are received and encoded at low bitrates. Extensive simulation results have consistently shown that the proposed MDC system significantly outperforms other state-of-the-art MDC methods on coding performance with much lower computational complexity.

Redundancy controllable scalable unbalanced multiple description bitstream generation for peer-to-peer video streaming

In peer-to-peer video streaming, the robustness to peer and packet losses is regarded very important in order to enjoy a good quality of experience. Multiple description coding (MDC) schemes are known to provide high robustness to packet losses. In peer-to-peer streaming in addition to high robustness, efficient controllability of data rate and redundancy among the data streams from peers is also vital. In this paper, a novel framework for scalable multiple description coding scheme for peer-to-peer video streaming is presented by addressing these requirements. The proposed MDC solution is based on the multiple description scalar quantization (MDSQ) by addressing the joint decoding of unbalanced descriptions and addition of jointly decodable successive refinement layers to side descriptions. Firstly, the design conditions for MDSQ with constrained successive refinement to obtain scalable multiple description streams where the bit streams can be truncated at any point to obtain lower quality spatial temporal descriptions are firstly proposed. Then the design conditions for joint decoding of two or more side descriptions from different multiple description scalar quantizers, originating from various bin spread factors leading to controllable redundancy are proposed. These design conditions enable joint redundancy and data rate control for streams coming from different peers, thereby, enabling high robustness to packet losses as well as peer losses with the adaptability of redundancy levels and truncation of scalable streams. The proposed design constraints are used within the motion compensated temporal filtering (MCTF) framework to demonstrate its advancement in robust peer-to-peer video streaming. The results show significant improvements over conventional MDC based on simple MSDQ and over single description scalable video.

A Mixed Layer Multiple Description Video Coding Scheme

Multiple description coding (MDC) is a technique where multiple streams from a source video are generated, each individually decodable and mutually refinable. MDC is a promising solution to overcome packet loss in video transmission over noisy channels, particularly for real-time applications in which retransmission of lost information is not practical. A problem with conventional MDC is that the achieved side distortion quality is considerably lower than single description coding (SDC) quality except at high redundancies which in turn leads to central quality degradation. In this paper, a new mixed layer MDC scheme is presented with no degradation in central quality, and providing better side quality (approximately as much as that of SDC) compared to conventional methods. Also, this property directly leads to higher average quality when delivering the video in lossy networks. For each discrete cosine transform coefficient, we generate two coefficients: base coefficient (BC) and enhancement coefficient which are combined together. When all descriptions are available, they are decomposed and decoded to achieve high quality video. When one description is not available, we use estimation to extract as much of the BC as possible from the received description. Simulation results show that the proposed scheme leads to an improved redundancy-rate-distortion performance compared to conventional methods. The algorithm is implemented in JM16.0 and its performance for two-description and four-description coding is verified by experiments.

Exploiting multiple description coding for intermediate recovery in wireless mesh networks

Guarding against channel errors in wireless networks has been a challenging research problem, specially when transmitting time-constrained contents, like streaming video or image. Multiple description coding (MDC) is an effective means to combat bursty packet losses over wireless channels, and it is especially promising for the applications where retransmission is unacceptable. In MDC, a frame is broken into several equally important descriptions which can be sent over multiple paths to the destination. Meshed multipath routing over wireless mesh networks and MDC, when combined together, could make video/image transmission more error-resilient by providing opportunities to recover erroneous video packets at the intermediate nodes along the route.In this work, we propose to combine MDC and meshed multipath routing in such a way that multiple descriptions are sent over different paths in the network and are merged at the intermediate nodes for possible recovery of corrupted descriptions. The routing uses the idea that when multiple descriptions join at intermediate points it can help in partial recovery of lost or corrupted descriptions by using the link error information. This approach reduces the possibility of error propagation, thereby improving the overall image/video quality at the destination. In order to achieve high gain in terms of peak signal-to-noise ratio (PSNR), we investigate an optimum spatial interleaving based MDC scheme that maximizes the intermediate recovery possibility for a given recovery filter design. We also explore the choice of an optimum number of descriptions for merging at an intermediate merging point that maximizes the PSNR gain. Our simulation study shows that, by introducing recovery possibility even at one intermediate node, it is possible to achieve a PSNR gain of around 5–6dB using our coding, routing, and recovery strategies.

Multiple Description Coding with Side Information: Practical Scheme and Iterative Decoding

Multiple description coding (MDC) with side information (SI) at the receiver is particularly relevant for robust transmission in sensor networks where correlated data is being transmitted to a common receiver, as well as for robust video compression. The rate-distortion region for this problem has been established in (Vaishampayan 1993). Here, we focus on the design of a practical MDC scheme with SI at the receiver. It builds upon both MDC principles and Slepian-Wolf (SW) coding principles. The input source is first quantized with a multiple description scalar quantizer (MDSQ) which introduces redundancy or correlation in the transmitted streams in order to take advantage of the path diversity. The resulting sequences of indexes are SW encoded, that is, separately encoded and jointly decoded. While the first step (MDSQ) plays the role of a channel code the second one (SW coding) plays the role of a source code, compressing the sequences of quantized indexes. In a second step, the cross-decoding of the two descriptions is proposed. This allows us to account for both the correlation with the SI as well as the correlation between the two descriptions.

H.264/AVC-based multiple description video coding using dynamic slice groups

In this paper, an H.264/AVC-based multiple description video coding scheme is proposed. It utilizes the advanced video coding tools and features provided in H.264/AVC to introduce redundancy into descriptions. Two independently decodable descriptions are generated, each consisting of two slice groups. One of them, called main slice group (MSG), is encoded normally as main information. The other one, called side slice group (SSG), is encoded with fewer bits as redundancy information by using larger quantization step sizes. Spatial and temporal correlations between neighboring macroblocks in video frames are exploited to achieve efficient redundancy coding. Experimental results show that the proposed MDC scheme is superior to previous slice group based multiple description coding (MDC) schemes in terms of the rate-distortion (R-D) performance.

Efficient Multiple-Description Image Coding Using Directional Lifting-Based Transform

This paper proposes an efficient two-description image coding technique. The two side descriptions of an image are generated by quincunx subsampling. The decoding from any side description is done by an interpolation process that exploits sample correlation. Although the quincunx subsampling is a natural choice for the best use of sample correlations in image multiple-description coding (MDC), each side description is not amenable to existing image coding techniques because the pixels are not aligned rectilinearly. We show how this difficulty can be overcome by an adaptive directional lifting (ADL) transform that is particularly suitable for decorrelating samples on the quincunx lattice. The ADL transform can be embedded into JPEG 2000 to construct a practical MD image encoder. Experimental results demonstrate that the proposed image MDC scheme can achieve good coding performance.

An H.264/AVC Video Coder Based on a Multiple Description Scalar Quantizer

Transmission of encoded video sequences over unreliable networks usually requires the adoption of protection techniques to guarantee good reconstruction quality at the receiver side. Multiple description coding (MDC) strategies add reliability to real-time video applications, where retransmission is not possible and packet losses afflict several frames degrading the overall quality. This paper presents a novel MDC scheme based on the H.264/AVC standard and a multiple description scalar quantizer which encodes the residual information into two descriptions. Finally, objective and visual performances are presented.

Distributed Temporal Multiple Description Coding for Robust Video Transmission

The problem of multimedia communications over best-effort networks is addressed here with multiple description coding (MDC) in a distributed framework. In this paper, we first compare four video MDC schemes based on different time splitting patterns and temporal two- or three-band motion-compensated temporal filtering (MCTF). Then, the latter schemes are extended with systematic lossy description coding where the original sequence is separated into two subsequences, one being coded as in the latter schemes, and the other being coded with a Wyner-Ziv (WZ) encoder. This amounts to having a systematic lossy Wyner-Ziv coding of every other frame of each description. This error control approach can be used as an alternative to automatic repeat request (ARQ) or forward error correction (FEC), that is, the additional bitstream can be systematically sent to the decoder or can be requested, as in ARQ. When used as an FEC mechanism, the amount of redundancy is mostly controlled by the quantization of the Wyner-Ziv data. In this context, this approach leads to satisfactory rate-distortion performance at the side decoders, however it suffers from high redundancy which penalizes the central description. To cope with this problem, the approach is then extended to the use of MCTF for the Wyner-Ziv frames, in which case only the low-frequency subbands are WZ-coded and sent in the descriptions.

Multiple description wavelet coding with dual decomposition and cross packetization

In this paper, a novel wavelet-based multiple description coding (MDC) is proposed with dual decomposition (DD) and cross packetization (CP). Through dual decomposition, each description has two parts, the primary and the complementary. The former contains the structural information, including the positions and signs of significant coefficients, whereas the latter contains the residual data, which are the absolute values of the significant coefficients’ magnitude. The primary part is most crucial for source reconstruction; hence, their codes generated by the x-tree wavelet encoder are duplicated in both descriptions for heavy protection. On the other hand, the residual data are processed by the multiple description scalar quantizer to generate two indices for their respective descriptions as the complementary part. The proposed DD–MDC method effectively enhances error-resilience capability for robust transmission. For the packet-switching networks, the proposed CP, which produces the row packets and column packets for the two descriptions, respectively, is incorporated into the DD–MDC framework, leading to the DDCP–MDC scheme. Extensive simulation results have clearly shown that the proposed wavelet-based DD–MDC and DDCP–MDC methods are highly error resilient and consistently yield high coding gain; particularly, when only one description is available, the reconstructed image quality is superior to that obtained with other existing methods.

An Improved Multiple Description Coding Strategy Based on Path Diversity

In this paper, a source coding technique exploiting packet path diversity is presented, which combines the individual benefits of MDC (multiple description coding) and LC (layer coding) for video transmission over wireless networks. Performance comparisons between LC and MDC are discussed at the beginning of this paper. Their advantages and disadvantages are concluded. An improved coding technique named auto-resilient multiple description coding (ARMDC) is then shown for its ability to conjoin the merits and avoid the shortcomings of the above two coding schemes. Under the critical transmission conditions of error-prone wireless channels, ARMDC can make all the received packets useful, not just those consecutive from the first packet. At the same time, it can also process the feature of LC, creating a base-layer bit-stream to ensure the basic quality of video. Transmission policy of ARMDC varies with transmission environment and application limits to gain fine video quality. 3G mobile channels are simulated and then streams create by ARMDC, MDR (multiple description with restart) scheme and coding scheme without any LC or MDC are sent over the channels. Experiment results show that the decoded video sequences of ARMDC streams have better performance in R-D curve comparision than the other MDC scheme and also gain best personality effect because of the smooth sequence quality. This out-coming is well adapted to streaming and conversational applications in wireless environment.

Multiple description image and video coding for wireless channels

We consider the problem of efficient image/video transmission over wireless channels. Such a problem involves good compression rates and effectiveness in presence of channel failures. In this work, we use the multiple description coding (MDC) techniques, based on Wavelet Transforms, that have been shown to be powerful against channel failures. We propose a bit allocation procedure that dispatches the source redundancy between the different channels when compressing to a target bit rate with a bounded side distortion. In this way, we develop an MDC scheme well adapted to channel noise. Then, we extend this bit allocation to video. This extension uses the 3D scan-based DWT of Parisot et al. (MMSP, IEEE, New York, 2001); that involves scan-based MDC with rate or quality control. In this work we propose to adapt redundancy between the descriptors in function of channel model and state (BER). Furthermore, the channels can have time-varying states. We consider BSC channels, Gaussian channels, and UMTS channels. The method can be efficiently extended to other channels when the channel model that matches the channel behavior is known. We evaluate the performance of the proposed MDC image/video coder for two descriptions. In a first group of simulations, we compare our application with some different MDC techniques presented by Vaishampayan (IEEE Trans. Inform. Theory 39 (3) (1993) 821) and Servetto et al. (ICIP, IEEE, Chicago, USA, 1998; IEEE Trans. Image Process. 9 (5) (2000) 813–826). In a second group of simulations, we evaluate the robustness of the proposed MDC when submitted to different kinds of channels noise.